“We know that less than one percent of those infected will develop this more serious form of the disease,” said Fernando Gonzalez, lead epidemiologist for the city. “But we need to remember that there is the possibility of developing a serious neurologic illness such as encephalitis or meningitis.”

The symptoms of neurologic illness can include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, or paralysis. Experts said serious illnesses from the infection can affect people of any age, but that people older than 60 years old are at the greatest risk.

The Department of Health offered tips on preventing mosquito-borne illnesses:

Wear long-sleeved shirts and long pants

Remember to “Tip and Toss”: Drain standing water both inside and outside of your home

Stay in cool places with air conditioning and window and door screens to keep out mosquitoes

Use Environmental Protection Agency-registered insect repellents with one of the following active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus, or para-menthane-diol, but experts warn not to use insect repellent on babies younger than 2 months old

Officials also urge residents to report standing water or mosquito-breeding sites to the Environmental Services Vector Control Program at 311.